Computational fluid dynamics study on magnus force of an autonomous underwater helicopter

The underwater vehicles are always being disturbed by ocean current when they work under the sea. In this paper, the Magnus force of a new type autonomous underwater vehicle (AUV) named “autonomous underwater helicopter (AUH)”, a disk-shaped deep-sea underwater vehicle, was analyzed to help it move away from a deep-sea region with temporary ocean current. The simulation technique of the ANSYS-CFX solver based on viscous computational fluid dynamics (CFD) was employed to analyze the hydrodynamic performance of the spinning AUH in the uniform inflow conditions. The simulation results show that the AUH's spinning behavior can obviously alter the pressure distribution on the both sides of the AUH, hence resulting in a lateral force, i.e. Magnus force and this induced force enables the spinning AUH successfully move away from a sudden, transient and/or steady, uniform ocean current region with inflow velocities of 1–2 knots under the deep-sea conditions. Finally, this study provides an important reference about interdependent relationship between effective spinning speed of the AUH subjected to controlled propeller revolution, speed and range of the ocean current.

I. Introduction

The torpedo-shaped axisymmetric body is undoubtedly the main appearance of conventional type of autonomous underwater vehicles (AUVs) [1]–[2], but it has poor maneuverability in sway due to inefficiency of the control surfaces under low velocity condition whereas good linear motion performance due to its streamlined shape [3]. In response to the complex environment under the sea, a clear demand is required for the next generation of AUVs to travel deeper and being more maneuverable [4]–[5], hence a new type AUV named “autonomous underwater helicopter (AUH)”, a disk-shaped deep-sea underwater vehicle, was designed to meet the demand at the Ocean College of Zhejiang University, in 2016. The structural design and scale model of the AUH are shown in Figs.1–2. Fig.1.

The structural design of the AUH

Fig. 2.

The scale model of the AUH